The present invention relates to a thermal spray powder containing granulated and sintered yttria particles and a method for forming a thermal spray coating obtained by using such thermal spray powder.
In the field of manufacturing of semiconductor devices and liquid crystal devices, the microfabrication of the devices is performed by dry etching using plasma. There have been known techniques which involve providing a thermal spray coating in portions of semiconductor device manufacturing equipment and liquid crystal device manufacturing equipment which may be subjected to etching damage by plasma during the plasma process, whereby the plasma etching resistance of these portions is improved (refer to Japanese Laid-Open Patent Publication No. 2002-80954, for example). By improving the plasma etching resistance in this manner, the scattering of particles is suppressed, resulting in an improvement in the yield of devices.
A thermal spray coating used in such applications can be formed by plasma thermal spraying of a thermal spray powder containing, for example, granulated and sintered yttria particles. Although development of thermal spray powders aimed to improve the plasma etching resistance of thermal spray coatings has been carried out, a thermal spray powder capable of meeting required performance has not been obtained as of yet.